Sulfurized oils



Patented Jan. 6, 1948 UNITED STATES PATENT DFFiCE SULFURIZED OILS NoDrawing. Application November 23, 1944, Serial N0. 564,898

Claims. 1

This invention relates, as indicated, to lubrieating compositions andmore particularly to compositions for use in connection with thelubrication of the working parts of internal combustion engines, motorvehicles,- etc. And it is among the objects of the invention to providecompositions obviating the disadvantages of the usual petroleum oils.

It has long been known that sulphur compounds when added to lubricatingoils impart certain properties to the mixtures which are of greatervalue when these mixtures are used as lubricants for very heavy dutysuch as is encountered in the lubrication of automotive gears of thehypoid and spiral bevel types and other power transmission gears and forthe lubrication of cutting tools such as are used in cutting andthreading steel pipe. The exact manner in which these compounds, withrespect to the cutting lubricants, act to produce these results is notknown with any degree of certainty. It is much more than a matter ofincreased film strength which such compounds impart to lubricating oils,since, for each sulphur compound that may be added to a lubricating oilto increase its film strength, there is an optimum percentage abovewhich there is no tendency to obtain further increase with greaterpercentages of the addition agent. On the other hand, there seems to beno limit to the improvement of a cutting oil that can be obtained byincreasing its sulphur content, at least as far as the smoothness of themetal cut obtained with it is concerned.

Not all sulphur compounds have this beneficial effect on lubricants tothe same degree for the same amount of sulphur as will be brought out inthe examples given herein below; and to most of those now in use thereare certain definite objections'. The most common sulphur compounds usedfor blending with lubricating oils are the sulfuretted glycerides of theunsaturated fatty acids and these usually contain about 12% sulphur.Sulfuretted lard oil is a typical example. These compounds are notentirely satisfactory for blending purposes for several reasons. Thesulfuretted glycerides are very viscous, hard to handle, raise the pourpoint of the oil with which they are blended, have a very strong odor ofhydrogen sulphide, and are irritating to the skin of the operatorsworking with them, are not as stable as desired when in use and do notgive a good cut when used in a cutting lubricant, do not give a veryhigh film strength when used in an extreme using a large percentage ofthese sulphur base oils, cutting lubricants are obtained which arerather inefficient such as for example the cutting qualities concernedare objectionable on account of odor, are irritating to the skin of theoperators and in case Of slight cuts on the hand cause sores difiicultto heal, are very viscous when cold, are not stable to high temperatureswhen in use, and break down and release Has. An extreme pressurelubricant for gears which is made from the conventional sulfurettedglycerides such as lard oil has many defects. In the first place, thistype of sulphur base blend is not as stable as is desired to the copperstrip corrosion test which some automobile manufacturers now require forsulphur base lubricants. Secondly, the film strength is not very high;and last, the pour point of the lubricants is raised 5 to 25 F.,depending upon the type of petroleum base oil used.

To the accomplishment of the foregoing and related ends, said inventionthen comprises the features hereinafter fully described and particularlypointed out in the claims, the following description setting forth indetail certain illustrative embodiments of the invention, these beingindicative, however, of but a few of the various ways in which theprinciple of the invention may be employed.

Broadly stated this invention is concerned with the blending in ahydrocarbon oil of a minor proportion of a halogenated sulphurized (orsulfuretted) monohydric or dihydric alcohol ester of an organic acid,and more particularly with the phenolic esters of organic acids for thepreparation of superior cutting oils, gear lubricants. crankcaselubricants, and the like.

The advantages of utilizing a compound containing both halogen andsulphur in a mono or dihydric alcohol ester of an organic acid are many.First, we combine the desirable properties of several addition agentscommonly used in complicated proportions into one additive. Secondly,the diiiiculties encountered with conventional sulphur additives, i. e.,odor, toxicity, increased pour point, stability, solubility, and etc.,are entirely.

group much more stable to heat than the sulfuretted glycerides andconsequently do not break down and release H23 in service as readily.When the glyceride breaks down, glycerine is released which forms gumand is generally objectionable.

When used in a cutting oil these halogenated sulphurized monohydric ordihydric alcohol esters of organic acids do not irritate the sinner theoperators. They are cheaper because about twice as much sulphur may beadded to this type of compound as can be added to the glycerides, andthus they give a more concentrated base.

Another important advantage of these synthetic esters, is that they aremore soluble in petroleum lubricants than their. correspondingsulfuretted glycerides. The latter have a marked bottom of the containerin which a blend of this type in a petroleum lubricant has stood forsome time. The reason for this phenomenon is that glycerides tend topolymerize on sulfuretting and form oil-soluble polymers whereas theircorresponding synthetic halogenated monhydric esters show little or'notendency to polymerize on sulfuretting or sulphurizing. The pour pointof blends made with a petroleum lubricant is higher, by to 25 F.(depending upon the type of tendency to showing sludge-like deposits onthe lubricant) when sulfuretted glyceride is used than;

when the corresponding sulfuretted or sulphur ized halogenated syntheticmonohydric alcohol ester is used. The latter compounds do not effect theemulsion characteristics and decrease the 4 temperatures and longertimes of sulphurizing are employed as described below.

Some examples of the esters we may sulphurize are given below, and it isto be understood that any of the phenolic components mentioned may becombined with any of the acid radicals mentioned to obtain furtherexamples of esters we may sulphurize. It is also to be understood thatthe following esters when sulphurized and blended with "mineral oil areto be considered as examples of our invention.

It is further to be understood that the time of introduction of thehalogen into the molecule is of little importance. Halogen may bepresent before esterification in either the acid or alcohol reactant. Itmay be introduced following the process of esteriflcation, or theproducts'of our application Serial No. 312,408, now Patent No.2,357,211, dated August 29, 1944, may be halogenated in any mannerconventional or otherwise.

Throughout the. foregoing description of our invention, reference hasbeen had uniformly to the halogens" generically. It is to be understoodthat the preferred halogen is chlorine, and next I in order ofimportance are fluorine, bromine, and iodine. The chlorinated speciesare generally preferable on account of their lower cost and ease ofpreparation. The fluorine species are of advantage, however, in thatthey are generally more stable than other halogens, and accordinglythose compounds which have a tendency toberelatively sludge formingtendencies of the bas oil with which they are blended. 0n the otherhand, the sulfuretted glycerides cause emulsion trouble and increasedsludge formation.

Th viscosity of the sulfuretted glyceride blends is very much higher forthe same amount of added sulphur at the same temperatures of 0 to 50 F.than similar blends where the halogenated sulfuretted or sulphurizedsynthetic monohydric aldifiicult to obtain a good flow of the cuttingoil from the sump of the machines on cold mornunstable will preferablybe combined with fluorine rather than any other 'of the halogens.

Chlorophenol esters of corn oil acids Iod oresorcinol esters of soy beanoil acids Guaiacol esters of chlorinated wool fat acids Esters ofB-hydroxyquinoline with brominated beeswax acids 1 Chlorocatechol estersof wool fat acids Chlorothymol esters of beeswax acids Phloroglucinolesters of chlorinated corn oil acids o-Cresol esters of chlorinatedbeeswax acids Iodophenol esters of sperm oil acids ings in a shop thatis not too well heated. Under these conditions, the machines do poorwork, and the cutting tools are dulled. The disadvantages of a high pourtest and a high viscosity at cold weather temperatures in the case ofgear lubricants are responsible for excess loss of power in' overcomingthe internal friction of the lubricant as well as difficulty in shiftingof gears in the case of automobile transmissions.

We have found more particularly that certainl synthetic esters of monoand dihydric phenols with organic acids are especially suited to su1-phurization and use when blended in mineral oils for lubricatingpurposes, and in more particular refinements of our invention we preferto use the halogenated species of the above described compounds. Themono and dihydric phenols which we may use may be monoor bior polycyclicand may contain various substituents and/or side chains in addition tothe one or two hydroxyl groups.

cluding the acids (free or combined) occurring in The organic acidswhich we may use to esterify such phenols are of various types, in-

natural fats, waxes and saponifiable oils, as well as synthetic acids.

prefer the unsaturated type because their esters are easier tosulphurize than the saturated type. The latter may be satisfactorilyused if higher Of these acids, however, we

Resorcinol esters of chlorinated acids of naturally occurringwaxes such.as camauba, candelilla, gondang, japan, montan, and bayberry waxesChlorophenolic esters of the acids of naturally occurring waxes such ascarnauba, candelilla, gondang, japan, montan, and bayberry waxesChloroquinol esters of. brominated corn oil acids B, Esters ofunsaturated organicacz'ds Xylenyl iodoethenate Chloroxylenylalpha-chioronaphthyloleate .Chlorothymyl heptenate Thymylchlorododecenate 'I'hymyl alpha-dichlorobenzyloleate Bromoguaiacoldilinoleate' Guaiacol alpha-chlorolaurylchlorocinnamate Dichloro-orcinylhexenate a-Naphthalenyl alpha-chloromethylbenzylchlorobutenateChloro-a-naphthalenyl alpha-chlorocresyllinoleate Bromoanthrenyl alphahydrogallylbromocinnamate Anthrenyl dichloro-octenate Chloroquinyldi-alpha-thymylpentenate Quinyl chlorolinoleate Dichloro diphenylbutenate Diphenyl alpha chloroethylbenzylchlorolinoleate 4Chlorolaurylphenyl heptenate Laurylphenyl alpha-chloromethylbenzyloleateChlorobutylphenyl didodecenate Chlorodecylchlorohydroquisoneylalpha-o-cresylchloroleate Chlorobenzyl-lauryl-chloro-resorcinoldodecenate Phenylbutylpyrogallyl alpha-chloropropylguaisylcinnamatePhenanthrenyl alpha-chlorodecylbenzylchlorolinoleateChlorocatechylpropylchloroanthrenyl methylnaphthal-cyclo-oleateDichlorostearylcatechyl octenate I Diiaromophenylalpha-chlorostearylnaphthylmellsate Naturally occurring oils and waxesas such containing monohydric alcohol esters of organic acids haveproved less satisfactory for use in this invention. The reason for thisappears to be that these naturally occurring substances are a mixture ofesters with naturally occurring impurities such as glycerides, highmolecular weight alcohols, hydrocarbons, often nitrogen compounds, andother impurities. Some of the oils and waxes in this group are sperm oiland similar whale oils,wool fat, or wool grease, beeswax, carnauba wax,and candelilla wax. Sperm oil contains from 5 per cent to 25 per cent ofglyceride, which makes it less satisfactory. It also contains anappreciable amount of free high molecular weight alcohols which areobjectionable, since they also give relatively unstable derivatives ofsulfurizing. The re-- moval of the monohydric or dihydric alcohol estersas such from the glycerides, free alcohol, and other impurities in thenaturally occurring material is not presently commercially feasible.

When sperm oil is sulfurized, a product is ob tained which does not lenditself to refining as do the sulfurized relatively pure syntheticesters; consequently it cannot be used in a crankcase lubricant as anoiliness and film strength improver or as a sludge inhibitor because ofits adverse effeet on color, emulsibility, and cloud test. Theobjectionable characteristics of the glycerides as described previouslyare in general also pertinent to the sulfurized and halogenatednaturally occurring esters with only a few exceptions.

Wool fat or wool grease contains monohydric alcohol esters but is notentirely satisfactory for use in our invention because of naturallyoccurring impurities found therein. These consist of alphaalkali saltsof fatty acids and free high molecular weight alcohols which yieldrelatively unstable sulfur derivatives. Sulfurized wool fat is not adesirable lubricating oil addition agent because it is not stable enoughto allow refining, and when added to mineral oils, the resultant blendwill not give a satisfactory emulsion or cloud test. Sulfurized wool fatdarkens the color of the oil. It also breaks down at relatively lowtemperatures (compared with sulfurized synthetic esters) and releasesHzS, which is objectionable. Hence wool fat would not give asatisfactory lubricating oil addition agent after suifurizing.

Beeswax contains 10 to per cent free fatty acid and 10 to 15 per centhydrocarbons and is therefore unsuited for the production of asulfurized addition agent for lubricating oils.

Candelilla wax contains, besides monohydric alcohol esters, about 10 percent or more free fatty acid and about 50 per cent hydrocarbons.Carnauba wax contains some monohydric alcohol esters, but these aremixed with a complex variety of impurities such as free fatty acids,hydrocarbons, and free high molecular weight alcohols; and thereforeneither candelilla nor carnauba wax is suitable for use as lubricatingoil addition agents after being sulfurized.

However, the above-mentioned materials, namely naturally occurring waxcontaining saponifiable oils, sperm oil and similar whale oils, woolfat, wool grease, beeswax, carnauba wax, and candelilla wax do containconsiderable quantities of high molecular weight acids (free andcombined) which are suitable for use in our invention aftersaponification and separation of the acids and esterification with amonoor di-hydric phenol. This renders usable the valuable acids of thenaturally occurring waxes and wax-containing saponifiable oils. Webelieve this is largely due to the decomposition of glycerides andremoval of the glycerol present in some of these materials, but we donot wish to be bound by this supposition but only by the appended claimsinterpreted as broadly as the prior art permits.

The sulfurization of our phenolic esters may be accomplished by heatingthe synthetic ester with sulfur or a halide of sulfur in the presence orabsence of a solvent. The temperature used depends on the particularsynthetic ester. About 350 to 380 F. is used on esters derived fromunsaturated acids and about 380 to 450 F. and higher may be used onsaturated esters. Volatile hydrocarbons or relatively non-volatileneutral oils may be used as solvents for the ester in the sulfurizingstep. The more volatile solvents of this type may be removed bydistillation with steam or in a vacuum while the higher boiling neutraloils may be left in the sulfurized ester if they are taken intoconsideration when subsequent blends are made.

In sulfurizing our phenolic esters we may use elemental sulfur orvarious compounds of sulfur including sulfur monochloride, sulfurdichloride,

phosphorus pentasulflde, phosphorus trisulfide, polysulfides, and thelike. Each of these reagents gives somewhat different products.Further-.

j er temperatures.

i ture within certain limits.

especially where bearing metals sensitive to corrosion are employed, ourproduct containing only inactive sulfur is preferred.

Various factors must be considered in the preparation of our halogenatedsulfurized phenolic esters containing active and inactive sulfur:

1. Reagents-In general for the preparation of halogenated sulfurizedphenolic esters containing active sulfur, we prefer to use elementalsulfur combined with short times of heating and low- The sulfurcompounds-such as chlorides of sulfur and sulfides of phosphorus aremore likely to give products containing only inactive sulfur and are notso flexible with regard to product, other factors being constant. It ispossible, however, at lower temperatures and with shorter periods ofheating especially in solvents. to obtain active sulfur containingproducts using small amounts of sulfur. By controlling reagents andconditions we are able to obtain sulfur bearing derivatives with 2 to 20per cent or more sulfur. tain products containing active sulfur orcontaining only inactive sulfur.

For any given sulfur content, we may ob- 3. Temperature.-Highertemperatures tend to fix .the sulfur in inactive combination and areused'when a stable halogenated sulfurized synthetic ester is desired.Use of lower temperatures with'the same reagents and otherwise the sameconditions gives products containing active sulfur which are especiallyuseful for cutting oils and extreme pressure gear lubricants whenblended with hydrocarbon oils and other ingredients.

4. Time.-We heat our reactants for. a relatively short time to producematerials with active sulfur and for a relatively long time to obtainonly inactive sulfur in our products. A short time at a high temperaturemay be selected which is the equivalent of a longer time at a lowertempera- There is, however, a most suitable range of temperature belowwhich the time required is unreasonably long,

5. Solvcnts.-Inert solvents may be employed;

and, in general, they have the effect of limiting the highesttemperature used in 'a particular sulfurization. If the solvent does notdissolve the sulfur or sulfur compound appreciably, the rate of reactionis slower and the formation of products containing active sulfur isfavored. If the solvent dissolves the sulfur or sulfur compound,

, the reaction proceeds more rapidly; and products containing onlyinactive sulfur are more readily obtained.

6. Unrefined products are more likely to contain active sulfur thanrefined products. We vary the quantities of refining reagents, forexample, sulfuric acid and clay, and also their concentration, time, andtemperature of contact, etc., to

8 obtain thorough refining when a very stable product is desired. Therefining may be milder or even omitted when an active sulfur product issought.

7. Pressure-Under superatmospheric pressure the sulfur is more stablyfixed in the same time and under the otherwise same conditions, and thisis useful modification of our process in order to obtain productscontaining only inactive sulfur.

While there is no specific limitation to th amount of added sulfur inthe form of halogenated sulfurized phenolic esters that should be usedin preparing different lubricants, usually 1 to 4 per cent or more maybe used for cutting oils; and about .5 to 2.5 per cent or more willusually be sufiicient for gear and other extreme pressure lubricants. Aslittle as .001 per cent or a little less and up to .25 per cent or moremay be used in oils for use in automobile crankcases.

The above ratios of sulfur to the petroleum base oil for its differentuses .are not intended to limit the scope of this invention, sincesmaller or larger que. \tities may be used in any case with resultswhich are partially satisfactory. They are given because generallyspeaking the optimum results can be obtained. by using the ratios withinthe limits that are suggested.

The hydrocarbon oils which are used in blending with the halogenatedsulfurized phenolic esters are not limitedto the hydrocarbon oils citedin the examples but are to include any oil of any type or viscosity suchas may be required by the lubricant in question. These different typesof oils may be unrefined mineral oil or oil refined by any method, suchas by the use of acids, alkalis, or solvents, or any combination of saidrefining processes. Other types are synthetic oils made bypolymerization of similar processes and hydrogenated oils.

Sulfur dioxide and carbon dioxide have been mentioned as agents forblowing halogenated sul-' furized synthetic esters and it is to beunderstood that the inventors are in no way limited to any particularrefining process and that other gaseous or liquid refining agents asnitrogen or alkali solutions and acid solutions may be used in refininghalogenated sulfurized phenolic esters of certain character and forcertain purposes.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

We therefore particularly point out and distinctly claim as ourinvention:

1. A lubricant comprising in combination a major proportion of an oil oflubricating viscosity and a minor proportion, sufilcient to increase thefilm strength of the oil, of a halogen-bearing sulfurized ester of aphenol and an unsaturated organic acid, said ester being ulfurized witha phosphorus.

2. A lubricant comprising in combination a major proportion of an oillubricating viscosity and a minor proportion, sufficient to increase thefilm strength of the oil, of a halogen-bearing sulfurized ester of aphenol and an unsaturated organic acid, said ester being sulfurized byphosphorus pentasulfide.

3. A lubricant comprising in combination a major proportion of an oil oflubricating viscosity and a minor proportion, sufficient to increase thefilm strength of the oil, of halogenated sulfurized phenyl oleate.

2,433,853 9 4. A lubricant comprising a combination a ma- REFERENCESCITED Jor proportion of an on of lubricating Viscosity The followingreferences are of record in the and a minor proportion, sufficient toincrease the me of this patent, film strength of the oil, of halogenatedsulfurized phenyllinoleate. 5 UNITED STATES PATENTS 5. A lubricantcomprising in combination a ma- Number Name Date jor proportion of anoil of lubricating viscosity 2 124 598 Turner July 26 1938 and a minorproportion, sufficient to increase the 2153496 Berger et aL Apr 1939film strength of the oil, of halogenated sulfurized 2'179062 Smith 1939phenyl esters of the acids naturally occurring in 10 2186646 'g' Jam1940 sperm 2:217:764 Morway et al Oct. 15, 1940 BERT LINCOLN- 2,31s,o13Prutton May 4, 1942 WALDO STEINER- 2,357,211 Lincoln et a1 Aug.29,1944

Certificate of Correction Patent No. 2,433,853. January 6, 1948.

t BERT H. LINCOLN ET AL.

It is hereby certified that errors appear in the printed specificationof the above numbered patent requiring correction as follows: Column 8,lines 62 and 63, claim 1, after the word phosphorus and before theperiod insert sulphide; line 65, claim 2, after oil insert of; column 9,line 1, claim 4, for a after comprising read in; and that the saidLetters Patent should be read with these corrections therein that thesame may conform to the record of the case in the Patent Office.

Signed and sealed this 30th day of March, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

